Google "steganography." You can significantly increase the bit rate. For example, overlay a QR code over each of four consecutive frames. You can do this witho

Google "steganography." You can significantly increase the bit rate. For example, overlay a QR code over each of four consecutive frames. You can do this without frame dropping. You only need to add about 6dB of the code for this to be recoverable. Similarly, if you know how the codec works, you can exploit that. (Your proposed method is actually pessimal for a modern B frame codec!) Then there is hiding modem transmissions in techno music sound tracks ;-)